What do i do if my friend is really depressed but her mom doesn't believe in medication?

i have to take medication for my depression and it really helps i believe that my friend needs to go to the doctor and get some test done or something and then her mom needs to rethink about medication because my friend is so depressed that she scratches herself very deep and it scares me and i have told her that.she wants medication but her mom says that she is not depressed when she really is. And im scared for my friend i am afraid she is one day shes going to kill herself and i don't want that to happen.